1. Field of the Invention
The invention relates to a system and method for updating a digital map for a driver assistance system in a vehicle.
2. Related Art
Driver assistance systems are used for assisting a driver in driving a vehicle, particularly for increasing driving convenience and for easing the burden on the driver, for example by performing navigation functions. In this case, it is possible for the driver assistance system to control the vehicle to some extent or else completely automatically, which is sometimes called semi-automated or highly automated driving. In the text which follows, driver assistance systems are also intended to be understood to mean such systems as are used to improve road safety, that is to say that contribute to preventing traffic accidents or, in the event of a traffic accident, to limiting personal injury and material damage as much as possible.
To perform these tasks, driver assistance systems access digital maps. Digital maps depict a physical region of space (usually part of the Earth's surface), subsequently also called the overall region, and contain map data for characterizing subregions of this overall region. The subregions may be defined by means of a regular or random grid. Each of these subregions has precisely one associated information unit in the digital map, that is to say precisely one map data item. Each map data item comprises the respective coordinates of the associated subregion and also attributes that contain information about this subregion. Thus, the attributes of a digital map contain lane and direction information for the roads in a road system and also the names of the roads, inter alia, for navigation functions. By way of example, the coordinates used for a subregion may be the coordinates of the physical center of the subregion or of another point within the subregion if the subregions are larger than permitted, in principle, via the physical resolution of the digital map.
For purposeful access to the information stored in the digital map, a vehicle furthermore has a position-finding unit (GPS or the like), for example a satellite navigation receiver, which can be used to ascertain a current position, that is to say current coordinates, of the vehicle. These coordinates can be used by the driver assistance system to read information from the digital map about the current surroundings of the vehicle and to subsequently use said information for performing its functions.
In this case, as the complexity of the functions of a driver assistance system increases, so too do the demands on the digital map that the driver assistance system accesses for performing these functions. In particular, there is an increase in the demands on the currentness of the information that the digital map contains and also on the volume, precision and also the type of this information.